Thar desert among areas facing endemic fluorosis: PCSIR experts

HYDERABAD, June 7 (APP): Thar Desert area of Sindh province is among Pakistan’s areas which are experiencing endemic fluorosis on regional scale. Muhammad Tahir Rafique, Senior Scientific Officer, Pakistan Council of Scientific Industrial Research (PCSIR) Karachi said here Friday defending his Ph.D thesis “Occurrence, Distribution and Origin of Fluoride-Rich Groundwater in the Thar Desert, Pakistan,” here at a seminar.

The research was carried out by him in the National Center of Excellence in Analytical Chemistry, University of Sindh (SU) under a joint venture project with Pakistan Council for Scientific and Industrial Research (PCSIR) and Department of Geology, University of Karachi (KU).

The seminar was attended by a large number of faculty members from various teaching institutes and departments and also research scholars enrolled for M.Phil and Ph.D research programme.

In his presentation, research scholar Muhammad Tahir Rafique said the present study confirms high fluoride in the groundwater of study area.

He said through research it was found that 78.77% of the analysed groundwater samples have fluoride values exceeding the limit of 1.5 mg/L proposed by the WHO.

He pointed out that distribution patterns show that high fluoride groundwater is concentrated along the north and northeastern side of Thar Desert especially in Chahchro and Umarkot areas, whereas localised enrichments have also been investigated in Mithi, Islamkot and Nagarparkar areas.

Scholar Tahir Rafique said the elevated fluoride levels have been investigated in almost all parts of the study areas whereas local population is consuming water with fluoride concentration as high as 5-30 mg/L and added that consequently, fluorosis problem can be visualised at various intensity levels in the study area from dental fluorosis to skeletal fluorosis, and non-skeletal manifestations to premature ageing.

The scholar said Fluoride is considered beneficial to human health if taken in limited quantity (0.5 to 1.5 mg/L) and added that it is also known to cause dental and skeletal fluorosis, osteoscalerosis, thyroid, and kidney problems if its concentration exceeds 1.5 mg/L in drinking water.

The scholar further said the chronic intake of excessive fluoride leads to severe and permanent bone and joint deformations in skeletal fluorosis, for which early symptoms include sporadic pain and stiffness of joints and finally the spine, major joints and muscles and the nervous system are damaged.

He said severe forms of fluorosis typically develop only when the fluoride concentration of drinking water is greater than 5 to 10 mg/L. However, symptoms of this disease can develop with regular ingestion of water containing fluoride concentrations as low as 1 to 2 mg/L. Whether, dental or skeletal, fluorosis is irreversible and no remedy and treatment so far exists, the only remedy is prevention by keeping fluoride intake within the safe limits, he added.

The research scholar said the occurrence of high fluoride concentrations in groundwater and the risk of fluorosis, associated with using such type of water for human consumption, is a serious problem faced by many countries in the world.

He said India, China, Mexico, the Rift Valley countries in East Africa have been identified as the worst affected countries.

The scholar pointed out that according to WHO there are more than 29 developed and developing nations that are endemic for fluorosis across the globe and added that many of these areas are arid and alternative sources of water are not available.

He pointed out that the main source of fluorine in groundwater is basically the minerals present in granitic rocks through which the groundwater percolates under variable temperature conditions and added that when fluoride- rich minerals, present in these rocks and soils, come in contact with water of high alkalinity, they release fluoride into groundwater through hydrolysis replacing hydroxyl (OH) ion.

According to the scholar fluoride- bearing granite rocks provide the source of dissolved fluoride in groundwater resources of Thar Desert. He added that elevated fluoride levels have been investigated in almost all parts of the study areas whereas local population is consuming water with fluoride concentration as high as 5-30 mg/L.

He said a detailed hydrochemical investigation of 425 groundwater samples collected from Umarkot, Mithi, Chachro, Diplo and Nagarparkar sub-districts of Thar Desert have been carried out for the major ions as well as trace metals’ analyses.

He further said the correlations between these elements and fluoride ion have been evaluated, and as a result full speciation calculations have been performed on these analyses.

In his concluding comments the scholar said according to the present study, the groundwater of study area is not suitable for drinking purpose.

He said the grave situation established through this study requires immediate remedial actions including the installation of defluoridation and desalination plants by the concerned authorities.

The scholar said the results of the present study point to the need for public authorities to plan and implement comprehensive preventive measures to control the adverse affects of groundwater consumption and to adopt a policy of information and advisory services to increase the awareness about the problem.

Vice Chancellor University of Sindh (SU) Mazhar-ul- Haq Siddiqui who presided over the seminar, highly appreciated the research work carried out by the scholar and said the work of the scholar was of pure applied nature and meant for the betterment of people.